AbstractThe existence or questionability of “repressed memories” can be discussed as being a matter of definition. It seems, however, far‐fetched to consider all “lost” memories as caused by encoding problems, brain damage, forgetfulness, failure to disclose events, and so on. We argue that dissociative amnesia (DA) (or “psychogenic amnesia,” or “functional amnesia,” or, as we favor to call it, “mnestic block syndrome”) is caused by psychic alterations, but ultimately they can be traced to changes in the physiology of the brain, as we are of the opinion that all memory processes—positive or negative—alter brain functions, sometimes more permanently, sometimes transiently. We have proven this idea using functional imaging techniques, in particular fluoro‐deoxy‐d‐glucose positron emission tomography. Having investigated dozens of patients with severe and long‐lasting DA conditions, we believe it to be disrespectful to many (but not to all) of the affected patients to question their disease condition, which can be proven to be not caused by feigning, malingering, or direct brain damage.